PokerTracker

I added a couple of custom stats to a profile that has a ton of custom stats already. These stat's won't work. They do work if I add them to any other profile though. Also, built in stats work if I add them to the profile.

May I have reached some sort of limit for custom stats or custom columns?

I'm not aware of any such limit though I suppose it is possible. If you could export and attach your layout to a support ticket we'll take a look into what we can do for you here.